In a high-voltage circuit, especially in a high-voltage direct current circuit, for example, power grid, a current is relatively large in the circuit in case of an overcurrent fault (for example a short circuit). If a switch device is disconnected directly to interrupt the circuit, an arc discharge phenomenon may occur on the switch device, which does great harm to the switch device, greatly affects switch device performance, and even damages the switch device. With increasing capacity of a power grid, a short-circuit current also increases, and large arc discharge is easily caused upon disconnecting a switch device, thereby damaging a switch device.
Therefore, it is necessary to provide an improved circuit breaker to solve the foregoing technical problem.